Art of drying materials



Dec. 7, 1937. c. 5. JENNINGS ET AL ART OF DRYING MATERIALS Filed Sept. 17, 1934 4 Sheets-Sheet l Jizajerzions 'kester {527k arm? 4,44 .9

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Dec. 7, 1937. c. 5. JENNINGS ET AL 2,101,335

ART OF DRYING MATERIALS Filed Sept. 17, 1934 4 Sheets-Sheet 2 zz'rys 1 l I l Dec. 7, 1937. c. s. JENNINGS ET AL ART DRYING MATERIALS Filed Sept. 1'7, 1954 4 Sheets-Sheet 3 If fierard 6 Dec. 7, 1937. v c. S..JENN|NGS ET AL ART OF DRYING MATERIALS 4 Sheets-Sheet 4 Filed Sept. 17, 1934 fizejerzzari 67228262" L53 kruzz'rgys F 66 6% wry? Patented Dec. 7, 1937- UNITED "STATES ART OF DRYING MATERIALS Chester S. Jennings, Syracuse, N. Y., and Frank W. Gerard, Dayton, Ohio, assignors to The Lamson Company, Syracuse, N. Y., a corporation of Massachusetts Application September 17, 1934, Serial No. 744,332 1 Claim. (01. 34-24 This invention relates to an improvement in the art of drying materials and more particularly to drying methods and apparatus wherein the material to be dried is conveyed through a plurality of 5 compartments in a housing and has for its primary object the removal of moisture from the material during its passage through the housing by the action of a stream of conditioned air which flows through the compartments in a direction l opposite to that in which thematerial travels whereby the stream has its initial contact with the material as the latter is leaving the housing and its final contact with the material as it is entering the housing.

A further object of the invention resides in the employment of radiant heat for the removal of the moisture in conjunction with the action of the stream of conditioned air.

Another object of the invention resides in the :0 supply to the stream of conditioned air as it flows through the housing of additional air when required to render the operation of the air stream more eficient.

These and other objects of the invention will 0 Fig. 1 is a side view partially in section illustrating one form of apparatus embodying this invention;

Fig. 2 is a plan view of such apparatus; Fig. 3 is a view in elevation of the side opposite that shown in Fig. l; I

Fig. 4 is an end view of such apparatus; Fig. 5 is a side view of the housing structure the doors being omitted; Fig. 6 is an enlarged elevation of one end there- Fig. 7 is an enlarged detail sectional view of the housing taken along the lines 1-! of Fig. 5 and showing the manner in which the doors are mounted; and

Fig. 8 is a view similar to Fig. 1' of another form of apparatus embodying this invention.

The material .to be dried is conveyed through a housing H] in any suitable manner, as by the conveyor II, through a plurality of compartments l2 3 defined by horizontally arranged baiiie plates or partitions" I3 and M which provide passages l5 and I 6 respectively connecting the compartments at alternate ends. The compartments I 2 are considered as grouped in pairs defined by the baflie plates M. The conveyor may be of any desired type capable of transporting the material. As shown in the drawings the material to be dried is a web of textile fabric I1 and the conveyor comprises a pair of chains I8 provided with tenter pins which, in accordance with the well known 5 practice in the textile art, engage the edges of, the web. The chains l8 pass around pairs of sprockets l9 suitably arranged in the housing, one pair being located in each of the passages l5 and I6.

The housing It) as shown particularly in Figs. 5, 6 and 7 comprises a plurality of vertical upright U-beams to the inner faces of which are secured plates 2|. The edges of the plates 2| extend beyond the beams and fixed thereto are anglev lo beams 22 on which rest the baiile plates or partitions 3 and I4. Overlapping plates 23 close the sides of the housing at each end and are provided with notches through which the shafts of the sprockets I8 pass. Between'the vertical beams 20 20 are mounted removable doors 24 through which access may be had to pairs of compartments l2 between the baflie plates I4.

Each door 24 is flanged at each end and provided at the bottom with angle strips 25 and at 25 the top with an offset strip 26 spaced from the face of the door to form a pocket 21. The upper edge of'each door is bent inwardly and down to form a hook 28. Suitably secured to the lowest angle beam 22 at each side are strips 29 spaced 3 from the face of the beam to define a pocket 30. Vertically disposed above each strip 29' and secured to the angle beams which support the baflle plates H are provided angle clips 3|. As shown the top angle beam 22 is reversed so that the vertical flange extends upwardly instead of downwardly as in the other beams. The doors in the lowest row are mounted by inserting the vertical flanges of the angle strips 25 in the pockets 30 and engaging the hooks 28 with the clips 3|. The 40 vertical flanges of the angle strips 25 on the doors in the other rows are received in the pockets 2| of the doors just below and the hooks 28 engage the clips 3| with the exception of course that the hooks 28- of those doors in the top rows engage 4g the vertical flanges of the top angle beams 22.

The wall at the'right end of the housing as shown in Fig. 5 is similarly constructed having at the center vertical angle beams 35 and a plate 36 to which horizontal angle beams 31 are secured. The ends of thebaflleplates I! rest upon and are secured to the beams 31. The spaces at right and left of the plate 36 are closed by doors in the manner above described, strips 29 and clips 3| being provided as shown in Fig. 6.

The left end of the housing is open; suitably located cross beams, shown in dotted lines in Fig. 5, being fixed to the corner uprights and supporting the ends of the baille plates l3. The top and bottom of the housing are closed. Frames 38 at either side of the housing support the ends of the shafts for the sprockets I9 (see Fig. 2).

The housing I0 is completely enclosed within a casing 40 the open end resting against one wall of the'casing. Formed in this wall of the casing are adit and exit openings 4| and 42 respectively, by which the conveyor and material enter and leave the housing. It will be noted that theadit opening leads to the top compartment l2 and the exit opening leads from the bottom compartment. The baiile plates at the bottom of the top-compartment and at the top of the bottom compartment are inclined and pairs of sprockets l9 are mounted in the housing adjacent these openings. The openings are provided with gates 43 having apertures just the proper dimensions topermit the passage of the chains and fabric. Air seals such as curtains (not shown) may also be installed to prevent air from entering or escaping from the housing.

The conveyor chains pass around sprockets 44 in their journey outside the casing from the opening 42 to the opening 4|. The fabric web I1 fed over a roller 45 is engaged with the chains as they pass around the sprockets 44 and is disengaged from the chains as they pass around the sprockets l9 near the opening 42 and leaves the housing through an aperture 46 in the gate 43 of that opening. It will be understood that this disengagement of the web from the chains is due to the action either of gravity or of knockers (not shown) of any well known type. Doors 41, 48 and 49 are provided in the walls of the casing through which entry to the housing may be had.

As the material is conveyed through the housing the moisture therein is removed by the action of a stream of conditioned air flowing through the housing in a direction opposite to that in which the material travels. that the term moisture includes not only .water but other liquids or sizing depending upon the treatment to which the material has been previously subjected and that the ter'mconditioned air is used herein to designate air at a selected temperature and/or dew point, which air is of controlled temperature and humidity and with .particular reference to air whose moisture content has been reduced below that of the prevailing atmosphere.

The conditioned air is here shown to be supplied by a dehumidifier system of suitable type.

Such system comprises a plurality of dehumidifier units 50 where the moisture content of the air is reduced by the action of a lithium chloride solution and a regenerator unit 5| in which such solution is from time to time treated to restore its moisture absorbing properties. The air, having its temperature fixed at the desired level either before or after it has been treated in a dehumidifler unit 50 is supplied to the housing I! through a pipe .52. This pipe enters the bottom compartment J2 below the exit opening '42, the end of the baflie plate I 4 being bent downwardly as shown in Fig. 1. The stream of air under the impulse of one or more blowers it flows upwardly through the housing compartment and escape's'through a pipe 54 leading from the top compartment near the edit opening 4i.

Thus the initial contact of the .,air stream with the material takes place as thelatter'is leaving It will be understood the housing and the final contact with the material takes place as the latter is entering the housing. Hence the stream of air, being driest when it initially contacts the material which is at that time nearly dry, will quickly extract from the material at a relatively low temperature any excess of moisture therein above the amount considered desirable. As the contact of the stream with the material continues, the amount of moisture in the stream increases but since the evaporative tendency of the moisture in the contacted material also increases as the opening 4| is approached, the differential between the absorptive property of the air stream and the evaporative tendency of the moisture in the material contacted may consequently be kept at an effective level during the entire flow of the stream of air through the housing so that moisture is continuously and efficiently removed from the material.

For the purpose of assisting the extraction of moisture from the material supplementary heating means are provided in the housing. As shown in Fig. 1 this means comprises coils 60 supplied with steam from a header 6| and feed pipes 62 and 63. The coils like the compartments are grouped in pairs the supply of steam to each pair being controlled by valves 64 in accordance with the information supplied by thermostat bulbs 85. The header 6| and feed pipes 62 and 63 are arranged in the casing at the side opposite the dehumidifier system and the pipes 63 enter the housing through openings 66 in the vertical beams 20. The valves 64 together with the indicator 6! controlled by the thermostat bulbs 65 may be located in a cabinet or recess 68 on the outer wall of the casing so that they are readily accesslb to the operators.

The-radiant heat thus supplied to the compartments by the coils is so regulated that the temperature of the compartment first traversed by the material is the highest and the temperature of the compartment last traversed is the lowest. Thus the greatest heat is supplied to the material as it is entering the housing and carrying the most moisture and the least heat is supplied to the material as it is leaving the housing substantially dry. Preferably the temperature of the first compartment traversed by the material is approximately 150 F. and that of the last compartment so traversed is approximately The surface, the heat of vaporization or a portion thereof being supplied by direct radiation to the material, and carried oif in the form of vapor by the stream of conditioned air. Moreover, the temperature of the air stream, as it flows through the housing, is raised so that its capability of absorbing moisture will be increased, and its eiliciency maintained throughout its flow.

In the casing wall is an inlet HI controlled by dampers II which may be opened or closed by any suitable means (a manually or automatically operated device 12 being indicated) Additional air may thus be admitted directly into the housing, which air mingles with and is carried along by the air stream flowing through the housing.

' As shown in Fig. 1 the inlet II is located about midway between the top and bottom of the housing and leads to the middle passage IS. The air stream has,by the time it reaches this passage, absorbed considerable moisture. from the material which it has already contacted and its temperature has been raised appreciably. The air. entering through the inlet being of a dew moisture in the material is thus brought to the point lower than that of the stream reduces the dew point of the stream and increases its absorbing properties. This is of considerable advantage because the material beyond the inlet with which the stream contacts carries more moisture than that already contacted.

The inlet 10 is opened preferably'when the material being dried is heavy and contains a large amount of moisture while when a light fabric having only a relatively small amount of moisture is being dried the inlet may be closed. The use of the inlet is also determined by the range of temperature to which thematerial may be subjected. When the allowable temperature is high a supply of additional air is often found not necessary since the air stream by reason of its higher temperature can absorb all the moisture required. On the other hand when the allowable temperature is lower, due for example to local conditionsor to the' l'eaction of the particular material to heat, the inlet may be opened since the additional air would increase the absorbing properties of the stream and at the same time hold the temperature down. The automatic control of the damper may be effected through the use of a thermostat (not shown) which will respond to the temperature or humidity within the housing or to both if so desired. The blower 53 at the outlet of the air from the housing is of sumcient strength to prevent the escape of the air stream through the inlet 10 and at the same time to draw the addi- .tional air into the housing.

The apparatus shown in Fig. 8 differs from that described above in that no coils for the supply of radiant heat directly to the material to be dried are provided. In that'apparatus heating units 15 which may be of suitable type, as for example steam coils or radiators, are mounted in the passages l6 connecting each pair of compartments defined by the bafiles l4. Suitable thermostats and valves (not shown) are provided for the regulation of the units 15. It will I be understood that the temperatures of the pairs of compartments will be varied in substantially the same way as in the apparatus shown in Figs.

the units I5 so that while its moisture content is increased by its passage over the material its capacity is also increased-and its effectiveness is maintained until it leaves the housing through the pipe 54. While only the pipes 52 and 54 are shown in Fig. 8 it will be understood that the apparatus also includes the dehumidifier and regenerator units shown and described as part of the apparatus set forth in Figs. 1 to '7.

While certain embodiments of this invention have been shown and described it will be understood that we are not limited thereto and that other embodiments may be made without departing from the spirit and scope of the invention as set forth in the'following claim.

We claim:

The steps in the drying of material which is conveyed into a housing having a plurality of connected compartments therein, through said compartments and out of the housing, which comprise subjecting the material to radiant heat as it passes through the compartments, the heat in the compartment first traversed by the material being greater than that in the compartment last traversed, setting up an air stream in the housing which flows through the compartments thereof in contact with the material and in the direction opposite to that in which the material travels, supplying conditioned air to the housing to constitute the initial portion of the air stream and supplying additional air to the housing at an intermediate compartment, which mingles with the conditioned air to constitute the final portion of the air stream, said additional air increasing the effectiveness of the air stream which at that point had been reduced below the efiectiveness of the conditioned air as it was supplied to the housing due to the moisture absorbed by the air stream in drying the material with which it had been in contact in the compartments it had fiowed through before reaching the compartment at which the additional air was supplied, whereby drying of the material is performed by the air stream in two stages, first by the mingled air which constitutes the final portion of the air stream and second by the conditioned air which constitutes the initial portion of the air stream.

CHESTER S. JENNINGS.

W. GERARD. 

